The present invention relates to a disk drive apparatus that allows stable recording and playback by suppressing undesirable vibration and noise caused by the unbalance of a disk as a removable recording medium.
Recently, in a disk drive apparatus for driving disks as removable recording media (for example, CD-ROM), it has been proceeding to increase disk rotational speeds in order to increase data transfer speed. However, disks contain mass imbalance due to thickness nonuniformity, etc. If such disks are rotated at a high speed, a nonuniform centrifugal force (imbalance force) is exerted on the center of disk rotation, resulting in the problem that the vibration due to the imbalance force is transmitted to the entire apparatus. Since the magnitude of the imbalance force increases with the square of the rotational frequency, the vibration increase rapidly as the disk rotational speed is raised. Accordingly, rotating disks at high speed has involved the the problems that noise is generated by the vibration, that the bearing of the spindle motor for driving disks is damaged, and that stable recording and playback are impossible. A further problem has been that when a disk drive apparatus is built in a computer or the like, the vibrations are transmitted to other peripheral devices, causing ill effects.
Therefore, in order to increase data transfer rates by increasing disk rotational speeds, it has been necessary to suppress undesirable vibrations caused by disk imbalance.
An example of a conventional disk drive apparatus will be described below with reference to drawing.
FIG. 24 is a perspective view showing the conventional disk drive apparatus. In FIG. 24, a disk 1 is driven for rotation by a spindle motor 2, and a head 3 reads data recorded on the disk 1 or writes data to the disk 1. A head driving mechanism 5 consists of a rack and pinion or the like, and converts the rotary motion of a head driving motor 4 into a rectilinear motion which is transmitted to the head 3. By this head driving mechanism 5, the head 3 is moved radially across the disk 1. The spindle motor 2, the head driving motor 4, and the head driving mechanism 5 are mounted on a sub-base 6. Vibration and shock transmitted to the sub-base 6 from outside the apparatus are dampened by an insulator 7 (elastic member); the sub-base 6 is mounted on a main base 8 via the insulator 7. Main part of the disk drive apparatus is constructed so that it can be mounted inside a computer apparatus or the like by using a frame 9 attached to the main base 8.
FIG. 25 is a cross-sectional side view showing the vicinity of the spindle motor 2 in the conventional disk drive apparatus. A turn table 110 is fixed to a shaft 21 of the spindle motor 2 and supports a clamp area 11 of the disk 1 in rotatable fashion. A boss 14 which engages with a clamp hole 12 in the disk 1 is formed integrally with the turn table 110. The centering of the disk 1 is achieved by engaging the disk 1 with the boss 14. In the upper part of the boss 14 is formed a positioning hole 113, and further, a counter yoke 15 is fixed.
A clamper 116 has a center projection 17 for centering, which engages with the positioning hole 113 formed in the turn table 110, and around which a ring-shaped magnet 18 is fixed. A flat contacting portion 19 which contacts the disk 1 is formed on the lower surface of the clamper 116.
In the thus constructed conventional disk drive apparatus, when loading the disk 1, the disk 1 is placed on the turn table 110 with the clamp hole 12 engaging on the boss 14. At this time, the disk 1 is held in position by the attractive force acting between the magnet 18 built into the clamper 116 and the counter yoke 15 fixed to the turn table 110. The thus held disk 1 is driven for rotation by the spindle motor 2 in integral fashion with the turn table 110 and the clamper 116. When removing the disk 1, the clamper 116 and the turn table 110 are driven by the driving force of a disk loading motor (not shown) in such direction that both depart from each other, so that the disk 1 becomes in a state to be removable.
However, with the conventional disk drive construction described above, if the disk 1 contains mass imbalance due to thickness nonuniformity, etc., when the disk 1 is rotated at high speed a centrifugal force (imbalance force) F acts upon the center of mass, G1, of the disk 1 shown in FIG. 25. Its acting direction turns with the rotation of the disk 1. This imbalance force F is transmitted to the sub-base 6 via the turn table 110 and spindle motor 2; since the sub-base 6 is supported on the insulator 7 formed of an elastic member, the sub-base 6 wobbles greatly because of the imbalance force, while deforming the insulator 7. Since the magnitude of the imbalance force F is proportional to the product of its unbalance amount (expressed in gcm) and the square of the rotational frequency, the vibration acceleration of the sub-base 6 also increases rapidly, approximately in proportion to the square of the rotational frequency of the disk 1. As a result, noise is generated by resonances of the sub-base 6 itself and the head driving mechanism 5 mounted on the sub-base 6, and the disk 1 and the head 3 vibrate greatly, leading to the problem that stable recording and playback cannot be made.
In order to coupe with this problem, in the conventional disk drive apparatus such a measure has been taken as to reduce the amplitude of vibration of the sub-base 6 by increasing the spring constant of the insulator 7 or by inserting an elastic member such as a plate spring between the sub-base 6 and the main base 8. Increasing the stiffness of the joint portion between the sub-base 6 and the main base 8, however, has lead to the problem that when vibration or shock is applied from outside the apparatus, the vibration or shock is directly transmitted to the sub-base 6 on which the disk 1, the head 3, etc. are mounted, rendering stable recording and playback impossible and degrading the anti-vibration, anti-shock characteristics of the apparatus.
The above measure has also involved the problem that the vibration of the sub-base 6 caused by the imbalance force F is transmitted to the outside of the disk drive apparatus via the main base 8 and frame 9, causing ill effects to other devices than the disk drive apparatus, which are mounted inside the computer apparatus. Furthermore, there has arisen the problem that a large side pressure is exerted on the bearing of the spindle motor 2 by the imbalance force F, increasing bearing damaging torque and leading to damage to the bearing, eventually shortening the bearing life.
In view of the above-outlined problems, the present invention provides a disk drive apparatus that ensures stable recording or reproducing even when an unbalanced disk is rotated at high speed, and that has high reliability against shock and vibration from outside the apparatus and achieves high data transfer rates by rotating the disk at high speed.
In order to solve the above-mentioned problems, the disk drive apparatus of the present invention is constructed such that a balancer having a hollow ring member containing therein a plurality of spherical bodies or a liquid is mounted so as to be rotatable integrally with a disk loaded into the disk drive apparatus; hereinafter, specific means will be shown.
A disk drive apparatus according to the present invention comprises:
a sub-base to which a spindle motor for rotationally driving a loaded disk is fixed;
a main base on which the sub-base is mounted via an elastic member; and
a balancer mounted rotatably in integral fashion with the loaded disk, and having a hollow ring member containing therein a plurality of spherical bodies.
Thus, according to the disk drive apparatus of the present invention, a disk drive apparatus can be achieved that has high vibration and shock resistant characteristics and that is capable of high-speed data transfer.
A disk drive apparatus according to the present invention comprises:
a sub-base to which a spindle motor for rotationally driving a loaded disk is fixed;
a main base on which the sub-base is mounted via an elastic member; and
a balancer mounted rotatably in integral fashion with the loaded disk, and having a hollow ring member in which a liquid is sealed.
Thus, according to the disk drive apparatus of the present invention, the vibration of the sub-base due to the unbalance of a loaded disk can be suppressed reliably.
A disk drive apparatus according to the present invention comprises:
a sub-base to which a spindle motor for rotationally driving a loaded disk is fixed;
a main base on which the sub-base is mounted via an elastic member; and
a balancer having a plurality of hollow ring members and mounted rotatably in integral fashion with the loaded disk,
wherein, of the plurality of hollow ring members, at least one hollow ring member contains spherical bodies therein, and the other hollow ring member contains a liquid sealed therein.
Thus, according to the disk drive apparatus of the present invention, the vibration of the sub-base can be suppressed reliably regardless of whether a disk with a large unbalance or a disk with a small unbalance is loaded.
A disk drive apparatus according to the present invention comprises:
a turn table for rotatably supporting a clamp area of the loaded disk; and
a clamper, which is formed integrally with the balancer, for clamping the disk in collaboration with the turn table.
Thus, according to the disk drive apparatus of the present invention, the vibration of the sub-base due to the unbalance of a loaded disk can be suppressed.
A disk drive apparatus according to the present invention comprises:
a turn table, which is formed integrally with the balancer, for rotatably supporting a clamp area of the loaded disk; and
a clamper for clamping the disk in collaboration with the turn table.
Thus, according to the disk drive apparatus of the present invention, the vibration of the sub-base due to the unbalance of a loaded disk can be suppressed, and stable recording or playback can be done.
In a disk drive apparatus according to the present invention, the balancer is provided in integral fashion with a rotor of the spindle motor.
Thus, according to the disk drive apparatus of the present invention, the vibration of the sub-base due to the unbalance of a loaded disk can be suppressed.
In a disk drive apparatus according to the present invention, the vibration resonance frequency of the sub-base due to deformation of the elastic member is set lower than the rotational frequency of the disk.
Thus, according to the disk drive apparatus of the present invention, a disk drive apparatus can be achieved that ensures stable recording or playback and that is capable of high-speed rotation, without degrading its anti-vibration, anti-shock characteristics.
In a disk drive apparatus according to the present invention, the primary resonance frequency of the sub-base due to deformation of the elastic member in a mechanical vibration in a direction parallel to the recording surface of the disk is set lower than the rotational frequency of the disk.
Thus, according to the disk drive apparatus of the present invention, since the vibration of the sub-base can be suppressed reliably irrespective of the magnitude of disk imbalance, a disk drive apparatus can be achieved that ensures stable recording or reproducing and that is capable of high-speed rotation, without degrading its anti-vibration, anti-shock characteristics.
In a disk drive apparatus according to the present invention, the primary resonance frequency of the sub-base due to deformation of the elastic member in a mechanical vibration in a direction parallel to the recording surface of the disk is set lower than the maximum rotational frequency of the disk.
Thus, according to the disk drive apparatus of the present invention, a disk drive apparatus can be achieved that ensures stable recording or reproducing and that is capable of high-speed rotation, without degrading its anti-vibration, anti-shock characteristics.
A disk drive apparatus according to the present invention comprises:
a turn table, which is provided with a positioning hole engaging with a spindle shaft of the spindle motor, for rotatably supporting the clamp area of the loaded disk; and
a clamper, which is provided with a center shaft engaging with the positioning hole, for clamping the disk in collaboration with the turn table,
wherein the hollow ring member is formed concentrically with a center axis of the clamper, and the balancer is formed integrally with the clamper.
Thus, according to the disk drive apparatus of the present invention, the vibration of the sub-base can be reduced further regardless of whether a disk with a large unbalance or a disk with a small unbalance is loaded.
A disk drive apparatus according to the present invention comprises:
a turn table, which is provided with a positioning hole engaging with a spindle shaft of the spindle motor, for rotatably supporting the clamp area of the loaded disk; and
a clamper, which is provided with a center hole engaging with the spindle shaft, for clamping the disk in collaboration with the turn table,
wherein the hollow ring member is formed concentrically with a center axis of the center hole in the clamper, and the balancer is formed integrally with the clamper.
Thus, according to the disk drive apparatus of the present invention, the vibration of the sub-base can be suppressed reliably regardless of whether a disk with a large unbalance or a disk with a small unbalance is loaded.
In a disk drive apparatus according to the present invention, two kinds of spherical bodies of different materials are arranged alternately and housed in the hollow ring member.
Accordingly, the disk drive apparatus of the present invention is capable of suppressing the generation of noise from the balancer itself.
In a disk drive apparatus according to the present invention, a plurality of metal spherical bodies and plastic spherical bodies are arranged alternately and housed in the hollow ring member.
Accordingly, the disk drive apparatus of the present invention is capable of suppressing the generation of noise from the balancer itself.
A disk drive apparatus according to the present invention comprises: a balancer with magnetic spherical bodies contained in the hollow ring member; and magnetic field generating means for holding the magnetic spherical bodies by attraction.
Accordingly, the disk drive apparatus of the present invention is capable of suppressing the generation of noise from the balancer itself.
A disk drive apparatus according to the present invention comprises:
a turn table, to which a counter yoke as a magnetic plate is fixed, for rotatably supporting the clamp area of the loaded disk; and
a clamper which has a built-in magnet for clamping the disk by an attractive force acting between the magnet and the counter yoke, and which is formed integrally with a balancer having magnetic spherical bodies contained in the hollow ring member.
Thus, according to the disk drive apparatus of the present invention, not only the vibration of the sub-base due to the unbalance of a loaded disk can be suppressed reliably, but the generation of noise from the balancer itself can also be suppressed, while keeping the number of components to a minimum.
In a disk drive apparatus according to the present invention, an elastic member is attached rigidly around the outer circumferential surface of the magnet to which the magnetic spherical bodies are made to adhere.
Accordingly, the disk drive apparatus of the present invention is capable of suppressing the generation of noise and vibration from the balancer itself.
A disk drive apparatus of the present invention is constructed such that an elastic member is attached rigidly to a back yoke which is a magnetic plate fixed to the opposite side of the magnet from the side thereof facing the counter yoke, and the magnetic spherical bodies are made to adhere to the elastic member of the back yoke.
Accordingly, the disk drive apparatus of the present invention is capable of suppressing the generation of noise and vibration from the balancer itself.
A disk drive apparatus according to the present invention comprises:
a turn table, to which a magnet is fixed, for rotatably supporting the clamp area of the loaded disk; and
a clamper which has a built-in counter yoke for clamping the disk by an attractive force acting between the magnet and the counter yoke, and which is formed integrally with a balancer having magnetic spherical bodies contained in the hollow ring member.
Thus, according to the disk drive apparatus of the present invention, not only the vibration of the sub-base due to the unbalance of a loaded disk can be suppressed reliably, but the generation of noise from the balancer itself can also be suppressed, while keeping the number of components to a minimum.
A disk drive apparatus according to the present invention is constructed such that an elastic member is attached rigidly to the counter yoke built into the clamper, and the magnetic spherical bodies are made to adhere to the elastic member.
Accordingly, the disk drive apparatus of the present invention is capable of suppressing the generation of noise and vibration from the balancer itself.
In a disk drive apparatus according to the present invention, the hollow ring member housing the spherical bodies is constructed from an upper case having an opening in a lower side thereof and a lower case having an opening in an upper side thereof, and a balancer is provided that has an elastic member sandwiched between an outer circumferential side wall of the upper case and an outer circumferential side wall of the lower case.
Accordingly, the disk drive apparatus of the present invention is capable of suppressing the generation of noise and vibration from the balancer itself.
In a disk drive apparatus according to the present invention, the hollow ring member housing the spherical bodies is constructed from an upper case having an opening in a lower side thereof and a lower case having an opening in an upper side thereof, and a balancer is provided that has an elastic member sandwiched between a lower end portion of an outer circumferential side wall of the upper case and a bottom upper surface of the lower case.
Accordingly, the disk drive apparatus of the present invention is capable of suppressing the generation of noise and vibration from the balancer itself.